/*
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 *    AttributeStats.java
 *    Copyright (C) 1999 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.core;

import java.io.Serializable;

/**
 * A Utility class that contains summary information on an the values that
 * appear in a dataset for a particular attribute.
 * 
 * @author <a href="mailto:len@reeltwo.com">Len Trigg</a>
 * @version $Revision: 1.10 $
 */
public class AttributeStats implements Serializable, RevisionHandler {

	/** for serialization */
	private static final long serialVersionUID = 4434688832743939380L;

	/** The number of int-like values */
	public int intCount = 0;

	/** The number of real-like values (i.e. have a fractional part) */
	public int realCount = 0;

	/** The number of missing values */
	public int missingCount = 0;

	/** The number of distinct values */
	public int distinctCount = 0;

	/** The number of values that only appear once */
	public int uniqueCount = 0;

	/** The total number of values (i.e. number of instances) */
	public int totalCount = 0;

	/** Stats on numeric value distributions */
	// perhaps Stats should be moved from weka.experiment to weka.core
	public weka.experiment.Stats numericStats;

	/** Counts of each nominal value */
	public int[] nominalCounts;

	/**
	 * Updates the counters for one more observed distinct value.
	 * 
	 * @param value
	 *            the value that has just been seen
	 * @param count
	 *            the number of times the value appeared
	 */
	protected void addDistinct(double value, int count) {

		if (count > 0) {
			if (count == 1) {
				uniqueCount++;
			}
			if (Utils.eq(value, (double) ((int) value))) {
				intCount += count;
			} else {
				realCount += count;
			}
			if (nominalCounts != null) {
				nominalCounts[(int) value] = count;
			}
			if (numericStats != null) {
				numericStats.add(value, count);
				numericStats.calculateDerived();
			}
		}
		distinctCount++;
	}

	/**
	 * Returns a human readable representation of this AttributeStats instance.
	 * 
	 * @return a String represtinging these AttributeStats.
	 */
	public String toString() {

		StringBuffer sb = new StringBuffer();
		sb.append(Utils.padLeft("Type", 4)).append(Utils.padLeft("Nom", 5));
		sb.append(Utils.padLeft("Int", 5)).append(Utils.padLeft("Real", 5));
		sb.append(Utils.padLeft("Missing", 12));
		sb.append(Utils.padLeft("Unique", 12));
		sb.append(Utils.padLeft("Dist", 6));
		if (nominalCounts != null) {
			sb.append(' ');
			for (int i = 0; i < nominalCounts.length; i++) {
				sb.append(Utils.padLeft("C[" + i + "]", 5));
			}
		}
		sb.append('\n');

		long percent;
		percent = Math.round(100.0 * intCount / totalCount);
		if (nominalCounts != null) {
			sb.append(Utils.padLeft("Nom", 4)).append(' ');
			sb.append(Utils.padLeft("" + percent, 3)).append("% ");
			sb.append(Utils.padLeft("" + 0, 3)).append("% ");
		} else {
			sb.append(Utils.padLeft("Num", 4)).append(' ');
			sb.append(Utils.padLeft("" + 0, 3)).append("% ");
			sb.append(Utils.padLeft("" + percent, 3)).append("% ");
		}
		percent = Math.round(100.0 * realCount / totalCount);
		sb.append(Utils.padLeft("" + percent, 3)).append("% ");
		sb.append(Utils.padLeft("" + missingCount, 5)).append(" /");
		percent = Math.round(100.0 * missingCount / totalCount);
		sb.append(Utils.padLeft("" + percent, 3)).append("% ");
		sb.append(Utils.padLeft("" + uniqueCount, 5)).append(" /");
		percent = Math.round(100.0 * uniqueCount / totalCount);
		sb.append(Utils.padLeft("" + percent, 3)).append("% ");
		sb.append(Utils.padLeft("" + distinctCount, 5)).append(' ');
		if (nominalCounts != null) {
			for (int i = 0; i < nominalCounts.length; i++) {
				sb.append(Utils.padLeft("" + nominalCounts[i], 5));
			}
		}
		sb.append('\n');
		return sb.toString();
	}

	/**
	 * Returns the revision string.
	 * 
	 * @return the revision
	 */
	public String getRevision() {
		return RevisionUtils.extract("$Revision: 1.10 $");
	}
}
